As physicians perform more and more surgery in a minimally-invasive manner, the techniques used to perform the surgery need to be improved. Among the primary motives are improvement of the procedure itself and the ease of performing a procedure so that physicians may more easily learn and execute the procedure. Patient comfort during and after the procedure should also be improved so that there are minimal side effects and after effects.
There are many procedures that require instruments to traverse the upper airway (nose, mouth, throat) of a patient, some extending all the way down the throat to the pulmonary or digestive system. Such procedures are usually performed with the patient awake, but often with “conscious sedation.” This technique may involve several different kinds of medications, including those to numb the passageways, another to help control coughing, and perhaps another to keep the patient relaxed. All of these procedures have in common the traversal of the throat, and all of them require some control of the gag reflex of the patient as the instrument proceeds through the passageway. Proper and facile advancement of the instrument through the airway is important to insure sufficient respiration during the entire period of the procedure.
Several techniques have been used to provide topical anesthesia for endotracheal intubation in a patient who is awake. One possible device is revealed in U.S. Pat. No. 5,072,726. This device uses high-frequency jet ventilation and requires an infusion pump to vaporize a local anesthetic. Another device, revealed by U.S. Pat. No. 5,571,071 is directed to delivery of a local anesthetic mist by a portion of a laryngoscope. This device and the procedure for using it supply virtually no air or oxygen to the patient during the delivery of the local anesthetic, and there does not appear to be a controlled delivery of the local anesthetic during the use of the device.
In one presently-known but unsatisfactory method, a physician injects 2–3 ml of a local anesthetic through the working channel of a flexible fiberscope into the airway passage, with or without an air/oxygen assist. The solution does not vaporize or atomize, and instead exits with a splash into the airway passage, typically irritating the patient. Subsequent coughing or choking of the patient (or both) may impede at least the fiberoptical view or orientation, but may even result in trauma caused by the fiberscope. The local anesthetic is thus not well-controlled nor is it well-distributed. Repeated administration due to insufficient topical anesthesia during endoscopy and intubation may result in overexposure of the patient to the local anesthetic.
None of these devices or techniques provides a simple, quick, and efficient way to aerate and deliver a local anesthetic in a fine mist to the airway passages. In addition, it would be beneficial to the patient to limit the amount of local anesthetic, in order to avoid any possible toxicity or adverse reactions. The present invention is directed at correcting these deficiencies in the prior art. What is needed is a relatively simple device that allows quick and efficient application of a small amount of local anesthetic resulting in sufficient topical anesthesia.